The posting coincides with the DNG Specification being updated to version 1.2. Tom Hogarty writes,

This update addresses several industry requirements for the DNG format including the formalization of the concept of a "camera profile" and a metadata tag to validate your image data. The definition of a camera profile for the DNG format as well as the allowance for multiple camera profiles to be embedded in a single DNG file will provide the industry with the ability to characterize raw data in an efficient and standardized format. (Think ICC profiles, but for raw data.)

Check out the rest of Tom’s post for more details on the changes. Developers can grab the updated DNG SDK here.